Non-stationary screw flow in a toroidal channel: way to a laboratory dynamo experiment

P. Frick - V. Noskov - S. Denisov - S. Khripchenko - D. Sokoloff - R. Stepanov - A. Sukhanovsky

Institute of Continuous Media Mechanics Korolyov 1, 614061 Perm, RUSSIA

Abstract
A possibility to implement a new type of dynamo experiment, namely, a nonstationary dynamo in a braked toroidal channel is considered. We suggest that a helical flow with the magnetic Reynolds number sufficient for screw dynamo action can develop in a toroidal channel with liquid sodium (about 100 kg) accelerated up to the frequency of 50 RPS and braked abruptly. The growth of the resulting magnetic field is expected to be sufficient to isolate dynamo effect. In this paper we present the results of hydrodynamic experiments with water prototypes. The spatial and temporal profiles of the helical flow excited in a braked channel by a diverter are investigated. Numerical simulation of the magnetic field evolution is performed for a helical flow with a profile extracted from the experimental data and scaled to the parameters of MHD apparatus. The data from the hydrodynamic experiment and the results of MHD numerical simulations are used to optimize the MHD apparatus under development. Table 1, Figs 18, Refs 19.